You know, I keep seeing that repeated, and the reason (I think...) was that t3 causes
an increase in the body's production of IGF binding proteins. But the whole advantage of the long r3 igf is that it's been modified so that it doesn't attach to those binding proteins (which would render it inactive), so I gotta wonder if this is just more armchair scientist speculation...which I am also doing, of course.

If that IS the reason, I'm thinking the use of the 2 together would probably not change things significantly. Do any of the real scientists/researchers/growth factor whizkids actually know...